In 2009, deadly ethnic riots erupted in Xinjiang after tensions flared between the Muslim Uighur minority and the Han Chinese.

There have also been a number of blasts in Xinjiang in the past, which the government blames on Uighur separatists.

But Uighur activists and human rights groups accuse Beijing of using the issue to crack down on Uighur dissidents, who have complained that waves of Han Chinese migrants have marginalised the Uighur culture.

China has poured troops into Xinjiang, which borders Central Asia, since the unrest in July 2009 in Urumqi which left about 200 people dead.

Rights group Amnesty International says more than 1,000 people have been detained in the wake of the violence.